diff --git a/build.nix b/build.nix
index 41247f9ca5..3e9c679cc1 100644
--- a/build.nix
+++ b/build.nix
@@ -33,7 +33,7 @@ in rec {
   # are not pure).
   maintainer-scripts = pkgs.dontRecurseIntoAttrs {
     update-hackage = import ./scripts/update-hackage.nix {
-      inherit (pkgs) stdenv writeScript coreutils glibc git
+      inherit (pkgs) stdenv lib writeScript coreutils glibc git
         openssh nix-prefetch-git gawk bash curl findutils;
       # Update scripts use the internal nix-tools and cabal-install (compiled with a fixed GHC version)
       nix-tools = haskell.internal-nix-tools;
@@ -41,7 +41,7 @@ in rec {
       inherit (haskell) update-index-state-hashes;
     };
     update-stackage = haskell.callPackage ./scripts/update-stackage.nix {
-      inherit (pkgs) stdenv writeScript coreutils glibc git
+      inherit (pkgs) stdenv lib writeScript coreutils glibc git
         openssh nix-prefetch-git gawk bash curl findutils;
       # Update scripts use the internal nix-tools and cabal-install (compiled with a fixed GHC version)
       nix-tools = haskell.internal-nix-tools;
diff --git a/builder/comp-builder.nix b/builder/comp-builder.nix
index 70087903e2..31a3c57c02 100644
--- a/builder/comp-builder.nix
+++ b/builder/comp-builder.nix
@@ -296,7 +296,7 @@ let
       homepage = package.homepage or "";
       description = package.synopsis or "";
       license = haskellLib.cabalToNixpkgsLicense package.license;
-      platforms = if platforms == null then stdenv.lib.platforms.all else platforms;
+      platforms = if platforms == null then lib.platforms.all else platforms;
     };
 
     propagatedBuildInputs =
diff --git a/builder/setup-builder.nix b/builder/setup-builder.nix
index a4429b1191..f2298a1684 100644
--- a/builder/setup-builder.nix
+++ b/builder/setup-builder.nix
@@ -56,7 +56,7 @@ let
         homepage = package.homepage or "";
         description = package.synopsis or "";
         license = haskellLib.cabalToNixpkgsLicense package.license;
-        platforms = if component.platforms == null then stdenv.lib.platforms.all else component.platforms;
+        platforms = if component.platforms == null then lib.platforms.all else component.platforms;
       };
 
       phases = ["unpackPhase" "patchPhase" "buildPhase" "installPhase"];
diff --git a/compiler/bootstrap/cabal-install.nix b/compiler/bootstrap/cabal-install.nix
index 57e0f991dd..0791b5d035 100644
--- a/compiler/bootstrap/cabal-install.nix
+++ b/compiler/bootstrap/cabal-install.nix
@@ -1,4 +1,4 @@
-{ fetchurl, hackage, stdenv, ghc, zlib, src, version }:
+{ fetchurl, hackage, stdenv, lib, ghc, zlib, src, version }:
 let dependencies =
  [ { name = "deepseq";           version = "1.4.3.0";   }
    { name = "binary";            version = "0.8.5.1";   }
@@ -42,7 +42,7 @@ in stdenv.mkDerivation ({
   };
 
   meta = {
-    platforms = stdenv.lib.platforms.all;
+    platforms = lib.platforms.all;
   };
 
   nativeBuildInputs = [ ghc zlib ];
diff --git a/compiler/ghc/configured-src.nix b/compiler/ghc/configured-src.nix
index b30ae246d7..8995b8ac6f 100644
--- a/compiler/ghc/configured-src.nix
+++ b/compiler/ghc/configured-src.nix
@@ -1,4 +1,4 @@
-{ stdenv, fetchurl
+{ stdenv, lib, fetchurl
 , ghc-version, ghc-version-date, ghc-patches, src-spec
 , targetPrefix
 , targetPlatform, hostPlatform
@@ -25,7 +25,7 @@ stdenv.mkDerivation (rec {
     nativeBuildInputs = [
         perl autoconf automake m4 python3 sphinx
         ghc bootPkgs.alex bootPkgs.happy bootPkgs.hscolour
-    ] ++ stdenv.lib.optional (patches != []) autoreconfHook;
+    ] ++ lib.optional (patches != []) autoreconfHook;
 
     # For building runtime libs
     depsBuildTarget = toolsForTarget;
@@ -33,10 +33,10 @@ stdenv.mkDerivation (rec {
     buildInputs = [ perl bash ] ++ (libDeps hostPlatform);
 
     propagatedBuildInputs = [ targetPackages.stdenv.cc ]
-        ++ stdenv.lib.optional useLLVM llvmPackages.llvm;
+        ++ lib.optional useLLVM llvmPackages.llvm;
 
-    depsTargetTarget = map stdenv.lib.getDev (libDeps targetPlatform);
-    depsTargetTargetPropagated = map (stdenv.lib.getOutput "out") (libDeps targetPlatform);
+    depsTargetTarget = map lib.getDev (libDeps targetPlatform);
+    depsTargetTargetPropagated = map (lib.getOutput "out") (libDeps targetPlatform);
 
     postPatch = "patchShebangs .";
 
@@ -54,7 +54,7 @@ stdenv.mkDerivation (rec {
         export CC="${targetCC}/bin/${targetCC.targetPrefix}cc"
         export CXX="${targetCC}/bin/${targetCC.targetPrefix}cxx"
         # Use gold to work around https://sourceware.org/bugzilla/show_bug.cgi?id=16177
-        export LD="${targetCC.bintools}/bin/${targetCC.bintools.targetPrefix}ld${stdenv.lib.optionalString targetPlatform.isAarch32 ".gold"}"
+        export LD="${targetCC.bintools}/bin/${targetCC.bintools.targetPrefix}ld${lib.optionalString targetPlatform.isAarch32 ".gold"}"
         export AS="${targetCC.bintools.bintools}/bin/${targetCC.bintools.targetPrefix}as"
         export AR="${targetCC.bintools.bintools}/bin/${targetCC.bintools.targetPrefix}ar"
         export NM="${targetCC.bintools.bintools}/bin/${targetCC.bintools.targetPrefix}nm"
@@ -64,13 +64,13 @@ stdenv.mkDerivation (rec {
 
         echo -n "${buildMK}" > mk/build.mk
         sed -i -e 's|-isysroot /Developer/SDKs/MacOSX10.5.sdk||' configure
-    '' + stdenv.lib.optionalString (!stdenv.isDarwin) ''
+    '' + lib.optionalString (!stdenv.isDarwin) ''
         export NIX_LDFLAGS+=" -rpath $out/lib/${targetPrefix}ghc-${version}"
-    '' + stdenv.lib.optionalString stdenv.isDarwin ''
+    '' + lib.optionalString stdenv.isDarwin ''
         export NIX_LDFLAGS+=" -no_dtrace_dof"
-    '' + stdenv.lib.optionalString targetPlatform.useAndroidPrebuilt ''
+    '' + lib.optionalString targetPlatform.useAndroidPrebuilt ''
         sed -i -e '5i ,("armv7a-unknown-linux-androideabi", ("e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64", "cortex-a8", ""))' llvm-targets
-    '' + stdenv.lib.optionalString targetPlatform.isMusl ''
+    '' + lib.optionalString targetPlatform.isMusl ''
         echo "patching llvm-targets for musl targets..."
         echo "Cloning these existing '*-linux-gnu*' targets:"
         grep linux-gnu llvm-targets | sed 's/^/  /'
@@ -86,10 +86,10 @@ stdenv.mkDerivation (rec {
             --replace '*-android*|*-gnueabi*)' \
                         '*-android*|*-gnueabi*|*-musleabi*)'
         done
-    '' + stdenv.lib.optionalString (src-spec.version != ghc-version) ''
+    '' + lib.optionalString (src-spec.version != ghc-version) ''
         substituteInPlace configure --replace 'RELEASE=YES' 'RELEASE=NO'
         echo '${ghc-version}' > VERSION
-    '' + stdenv.lib.optionalString (ghc-version-date != null) ''
+    '' + lib.optionalString (ghc-version-date != null) ''
         substituteInPlace configure --replace 'RELEASE=YES' 'RELEASE=NO'
         echo '${ghc-version-date}' > VERSION_DATE
     '';
@@ -99,16 +99,16 @@ stdenv.mkDerivation (rec {
     configureFlags = [
         "--datadir=$doc/share/doc/ghc"
         "--with-curses-includes=${ncurses.dev}/include" "--with-curses-libraries=${ncurses.out}/lib"
-    ] ++ stdenv.lib.optionals (targetLibffi != null) ["--with-system-libffi" "--with-ffi-includes=${targetLibffi.dev}/include" "--with-ffi-libraries=${targetLibffi.out}/lib"
-    ] ++ stdenv.lib.optional (!enableIntegerSimple) [
+    ] ++ lib.optionals (targetLibffi != null) ["--with-system-libffi" "--with-ffi-includes=${targetLibffi.dev}/include" "--with-ffi-libraries=${targetLibffi.out}/lib"
+    ] ++ lib.optional (!enableIntegerSimple) [
         "--with-gmp-includes=${targetGmp.dev}/include" "--with-gmp-libraries=${targetGmp.out}/lib"
-    ] ++ stdenv.lib.optional (targetPlatform == hostPlatform && hostPlatform.libc != "glibc" && !targetPlatform.isWindows) [
+    ] ++ lib.optional (targetPlatform == hostPlatform && hostPlatform.libc != "glibc" && !targetPlatform.isWindows) [
         "--with-iconv-includes=${libiconv}/include" "--with-iconv-libraries=${libiconv}/lib"
-    ] ++ stdenv.lib.optionals (targetPlatform != hostPlatform) [
+    ] ++ lib.optionals (targetPlatform != hostPlatform) [
         "--enable-bootstrap-with-devel-snapshot"
-    ] ++ stdenv.lib.optionals (disableLargeAddressSpace) [
+    ] ++ lib.optionals (disableLargeAddressSpace) [
         "--disable-large-address-space"
-    ] ++ stdenv.lib.optionals (targetPlatform.isAarch32) [
+    ] ++ lib.optionals (targetPlatform.isAarch32) [
         "CFLAGS=-fuse-ld=gold"
         "CONF_GCC_LINKER_OPTS_STAGE1=-fuse-ld=gold"
         "CONF_GCC_LINKER_OPTS_STAGE2=-fuse-ld=gold"
@@ -116,7 +116,7 @@ stdenv.mkDerivation (rec {
 
     outputs = [ "out" ];
     phases = [ "unpackPhase" "patchPhase" ]
-            ++ stdenv.lib.optional (ghc-patches != []) "autoreconfPhase"
+            ++ lib.optional (ghc-patches != []) "autoreconfPhase"
             ++ [ "configurePhase" "installPhase" ];
     installPhase = "cp -r . $out";
 })
diff --git a/compiler/ghc/default.nix b/compiler/ghc/default.nix
index 4aa53a0a3c..f8e0d55245 100644
--- a/compiler/ghc/default.nix
+++ b/compiler/ghc/default.nix
@@ -3,7 +3,7 @@
 # haskell.nix ships its own version of the ghc expression as it needs more
 # control over the expression to isolate it against varying <nixpkgs> and
 # allow us to customize it to the way haskell.nix works.
-{ stdenv, haskell-nix, targetPackages
+{ stdenv, lib, haskell-nix, targetPackages
 
 # build-tools
 , bootPkgs
@@ -26,7 +26,7 @@
 
 , # If enabled, GHC will be built with the GPL-free but slower integer-simple
   # library instead of the faster but GPLed integer-gmp library.
-  enableIntegerSimple ? !(stdenv.lib.any (stdenv.lib.meta.platformMatch stdenv.hostPlatform) gmp.meta.platforms), gmp
+  enableIntegerSimple ? !(lib.any (lib.meta.platformMatch stdenv.hostPlatform) gmp.meta.platforms), gmp
 
 , # If enabled, use -fPIC when compiling static libs.
   enableRelocatedStaticLibs ? stdenv.targetPlatform != stdenv.hostPlatform && !stdenv.targetPlatform.isAarch32
@@ -42,7 +42,7 @@
 
 , # What flavour to build. An empty string indicates no
   # specific flavour and falls back to ghc default values.
-  ghcFlavour ? stdenv.lib.optionalString haskell-nix.haskellLib.isCrossTarget (
+  ghcFlavour ? lib.optionalString haskell-nix.haskellLib.isCrossTarget (
     if useLLVM
       then "perf-cross"
       else "perf-cross-ncg"
@@ -82,7 +82,7 @@ let
   targetGmp = targetPackages.gmp or gmp;
 
   # TODO(@Ericson2314) Make unconditional
-  targetPrefix = stdenv.lib.optionalString
+  targetPrefix = lib.optionalString
     (targetPlatform != hostPlatform)
     "${targetPlatform.config}-";
 
@@ -93,52 +93,52 @@ let
     endif
     DYNAMIC_GHC_PROGRAMS = ${if enableShared then "YES" else "NO"}
     INTEGER_LIBRARY = ${if enableIntegerSimple then "integer-simple" else "integer-gmp"}
-  '' + stdenv.lib.optionalString (targetPlatform != hostPlatform) ''
+  '' + lib.optionalString (targetPlatform != hostPlatform) ''
     CrossCompilePrefix = ${targetPrefix}
-  '' + stdenv.lib.optionalString isCrossTarget ''
+  '' + lib.optionalString isCrossTarget ''
     Stage1Only = ${if targetPlatform.system == hostPlatform.system then "NO" else "YES"}
     HADDOCK_DOCS = NO
     BUILD_SPHINX_HTML = NO
     BUILD_SPHINX_PDF = NO
-  '' + stdenv.lib.optionalString enableRelocatedStaticLibs ''
+  '' + lib.optionalString enableRelocatedStaticLibs ''
     GhcLibHcOpts += -fPIC
     GhcRtsHcOpts += -fPIC
-  '' + stdenv.lib.optionalString targetPlatform.useAndroidPrebuilt ''
+  '' + lib.optionalString targetPlatform.useAndroidPrebuilt ''
     EXTRA_CC_OPTS += -std=gnu99
-  '' + stdenv.lib.optionalString (!enableTerminfo) ''
+  '' + lib.optionalString (!enableTerminfo) ''
     WITH_TERMINFO=NO
   ''
   # musl doesn't have a system-linker. Only on x86, and on x86 we need it, as
   # our elf linker for x86_64 is broken.
-  + stdenv.lib.optionalString (targetPlatform.isMusl && !targetPlatform.isx86) ''
+  + lib.optionalString (targetPlatform.isMusl && !targetPlatform.isx86) ''
     compiler_CONFIGURE_OPTS += --flags=-dynamic-system-linker
   ''
   # While split sections are now enabled by default in ghc 8.8 for windows,
   # the seem to lead to `too many sections` errors when building base for
   # profiling.
-  + stdenv.lib.optionalString targetPlatform.isWindows ''
+  + lib.optionalString targetPlatform.isWindows ''
     SplitSections = NO
-  '' + stdenv.lib.optionalString (!enableLibraryProfiling) ''
+  '' + lib.optionalString (!enableLibraryProfiling) ''
     BUILD_PROF_LIBS = NO
   '';
 
   # Splicer will pull out correct variations
-  libDeps = platform: stdenv.lib.optional enableTerminfo [ ncurses ]
+  libDeps = platform: lib.optional enableTerminfo [ ncurses ]
     ++ [targetLibffi]
-    ++ stdenv.lib.optional (!enableIntegerSimple) gmp
-    ++ stdenv.lib.optional (platform.libc != "glibc" && !targetPlatform.isWindows) libiconv
-    ++ stdenv.lib.optional (platform.isLinux && !platform.isAarch32) numactl;
+    ++ lib.optional (!enableIntegerSimple) gmp
+    ++ lib.optional (platform.libc != "glibc" && !targetPlatform.isWindows) libiconv
+    ++ lib.optional (platform.isLinux && !platform.isAarch32) numactl;
 
   toolsForTarget =
     if hostPlatform == buildPlatform then
-      [ targetPackages.stdenv.cc ] ++ stdenv.lib.optional useLLVM llvmPackages.llvm
+      [ targetPackages.stdenv.cc ] ++ lib.optional useLLVM llvmPackages.llvm
     else assert targetPlatform == hostPlatform; # build != host == target
-      [ stdenv.cc ] ++ stdenv.lib.optional useLLVM buildLlvmPackages.llvm;
+      [ stdenv.cc ] ++ lib.optional useLLVM buildLlvmPackages.llvm;
 
   targetCC = builtins.head toolsForTarget;
 
   configured-src = import ./configured-src.nix {
-    inherit stdenv fetchurl
+    inherit stdenv lib fetchurl
     ghc-version ghc-version-date ghc-patches src-spec
     targetPrefix
     targetPlatform hostPlatform
@@ -212,7 +212,7 @@ stdenv.mkDerivation (rec {
   nativeBuildInputs = [
     perl autoconf automake m4 python3 sphinx
     ghc bootPkgs.alex bootPkgs.happy bootPkgs.hscolour
-  ] ++ stdenv.lib.optional (patches != []) autoreconfHook;
+  ] ++ lib.optional (patches != []) autoreconfHook;
 
   # For building runtime libs
   depsBuildTarget = toolsForTarget;
@@ -220,14 +220,14 @@ stdenv.mkDerivation (rec {
   buildInputs = [ perl bash ] ++ (libDeps hostPlatform);
 
   propagatedBuildInputs = [ targetPackages.stdenv.cc ]
-    ++ stdenv.lib.optional useLLVM llvmPackages.llvm;
+    ++ lib.optional useLLVM llvmPackages.llvm;
 
-  depsTargetTarget = map stdenv.lib.getDev (libDeps targetPlatform);
-  depsTargetTargetPropagated = map (stdenv.lib.getOutput "out") (libDeps targetPlatform);
+  depsTargetTarget = map lib.getDev (libDeps targetPlatform);
+  depsTargetTargetPropagated = map (lib.getOutput "out") (libDeps targetPlatform);
 
   # required, because otherwise all symbols from HSffi.o are stripped, and
   # that in turn causes GHCi to abort
-  stripDebugFlags = [ "-S" ] ++ stdenv.lib.optional (!targetPlatform.isDarwin) "--keep-file-symbols";
+  stripDebugFlags = [ "-S" ] ++ lib.optional (!targetPlatform.isDarwin) "--keep-file-symbols";
 
   # See #63511 - the only unstripped file is the debug rts which isn't meant to
   # be stripped.
@@ -236,8 +236,8 @@ stdenv.mkDerivation (rec {
   checkTarget = "test";
 
   hardeningDisable = [ "format" ]
-                   ++ stdenv.lib.optional stdenv.targetPlatform.isAarch32 "pic"
-                   ++ stdenv.lib.optional stdenv.targetPlatform.isMusl "pie";
+                   ++ lib.optional stdenv.targetPlatform.isAarch32 "pic"
+                   ++ lib.optional stdenv.targetPlatform.isMusl "pie";
 
   postInstall = ''
     # Install the bash completion file.
@@ -250,7 +250,7 @@ stdenv.mkDerivation (rec {
       # The ghcprog fixup is for musl (where runhaskell script just needs to point to the correct
       # ghc program to work).
       sed -i \
-        -e '2i export PATH="$PATH:${stdenv.lib.makeBinPath [ targetPackages.stdenv.cc.bintools coreutils ]}"' \
+        -e '2i export PATH="$PATH:${lib.makeBinPath [ targetPackages.stdenv.cc.bintools coreutils ]}"' \
         -e 's/ghcprog="ghc-/ghcprog="${targetPrefix}ghc-/' \
         $i
     done
@@ -324,7 +324,7 @@ stdenv.mkDerivation (rec {
     inherit (ghc.meta) license platforms;
   };
 
-} // stdenv.lib.optionalAttrs targetPlatform.useAndroidPrebuilt {
+} // lib.optionalAttrs targetPlatform.useAndroidPrebuilt {
   dontStrip = true;
   dontPatchELF = true;
   noAuditTmpdir = true;
diff --git a/compiler/old-ghc-nix/default.nix b/compiler/old-ghc-nix/default.nix
deleted file mode 100644
index 7d8a396550..0000000000
--- a/compiler/old-ghc-nix/default.nix
+++ /dev/null
@@ -1,10 +0,0 @@
-{ pkgs ? import <nixpkgs> {} }:
-let
-  fetch = jsonFile:
-    with builtins;
-    let spec = fromJSON (readFile jsonFile);
-    in pkgs.fetchgit {
-      name = "old-ghc-nix";
-      inherit (spec) sha256 url rev;
-    };
-in import (fetch ./old-ghc-nix.json) { inherit pkgs; }
diff --git a/compiler/old-ghc-nix/old-ghc-nix.json b/compiler/old-ghc-nix/old-ghc-nix.json
deleted file mode 100644
index ac31221f58..0000000000
--- a/compiler/old-ghc-nix/old-ghc-nix.json
+++ /dev/null
@@ -1,7 +0,0 @@
-{
-  "url": "https://github.com/angerman/old-ghc-nix",
-  "rev": "2a41a09127f6dc7a6384823d1acd51ba257f95bd",
-  "date": "2020-06-03T12:50:09+08:00",
-  "sha256": "1cp6aksb6ldgjb5zyqikyjrjij79n9z7wd86migph0wp19vmszkf",
-  "fetchSubmodules": false
-}
diff --git a/docs/tutorials/cross-compilation.md b/docs/tutorials/cross-compilation.md
index b26cdaccd5..51063e6adf 100644
--- a/docs/tutorials/cross-compilation.md
+++ b/docs/tutorials/cross-compilation.md
@@ -90,7 +90,7 @@ executables you must add package overrides to:
 ```nix
 {
   packages.bench.components.exes.bench.configureFlags =
-    stdenv.lib.optionals stdenv.hostPlatform.isMusl [
+    lib.optionals stdenv.hostPlatform.isMusl [
       "--disable-executable-dynamic"
       "--disable-shared"
       "--ghc-option=-optl=-pthread"
diff --git a/nix/sources.json b/nix/sources.json
index 365f2698d3..5714b92985 100644
--- a/nix/sources.json
+++ b/nix/sources.json
@@ -119,6 +119,7 @@
     },
     "nixpkgs-unstable": {
         "branch": "nixpkgs-unstable",
+        "builtin": false,
         "description": "Nix Packages collection",
         "homepage": "",
         "owner": "NixOS",
@@ -128,5 +129,18 @@
         "type": "tarball",
         "url": "https://github.com/NixOS/nixpkgs/archive/410bbd828cdc6156aecd5bc91772ad3a6b1099c7.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "old-ghc-nix": {
+        "branch": "master",
+        "builtin": false,
+        "description": "Old and New GHC",
+        "homepage": null,
+        "owner": "angerman",
+        "repo": "old-ghc-nix",
+        "rev": "131ce9ae27d7b7afdd1d3ce8c3a74483e60b91bb",
+        "sha256": "0n62qr7hrqmy6h80736ji47ln759sk845g43f9cprpmcs9m4wl9i",
+        "type": "tarball",
+        "url": "https://github.com/angerman/old-ghc-nix/archive/131ce9ae27d7b7afdd1d3ce8c3a74483e60b91bb.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     }
 }
diff --git a/nix/sources.nix b/nix/sources.nix
index c59e1a1618..1938409ddd 100644
--- a/nix/sources.nix
+++ b/nix/sources.nix
@@ -6,52 +6,63 @@ let
   # The fetchers. fetch_<type> fetches specs of type <type>.
   #
 
-  fetch_file = pkgs: spec:
-    if spec.builtin or true then
-      builtins_fetchurl { inherit (spec) url sha256; }
-    else
-      pkgs.fetchurl { inherit (spec) url sha256; };
-
-  fetch_tarball = pkgs: spec:
-    if spec.builtin or true then
-      builtins_fetchTarball { inherit (spec) url sha256; }
-    else
-      pkgs.fetchzip { inherit (spec) url sha256; };
+  fetch_file = pkgs: name: spec:
+    let
+      name' = sanitizeName name + "-src";
+    in
+      if spec.builtin or true then
+        builtins_fetchurl { inherit (spec) url sha256; name = name'; }
+      else
+        pkgs.fetchurl { inherit (spec) url sha256; name = name'; };
 
-  fetch_git = pkgs: spec:
-    pkgs.fetchgit { url = spec.repo; inherit (spec) rev deepClone sha256; };
+  fetch_tarball = pkgs: name: spec:
+    let
+      name' = sanitizeName name + "-src";
+    in
+      if spec.builtin or true then
+        builtins_fetchTarball { name = name'; inherit (spec) url sha256; }
+      else
+        pkgs.fetchzip { name = name'; inherit (spec) url sha256; };
 
-  fetch_builtin-tarball = spec:
-    builtins.trace
-      ''
-        WARNING:
-          The niv type "builtin-tarball" will soon be deprecated. You should
-          instead use `builtin = true`.
+  fetch_git = name: spec:
+    let
+      ref =
+        if spec ? ref then spec.ref else
+          if spec ? branch then "refs/heads/${spec.branch}" else
+            if spec ? tag then "refs/tags/${spec.tag}" else
+              abort "In git source '${name}': Please specify `ref`, `tag` or `branch`!";
+    in
+      builtins.fetchGit { url = spec.repo; inherit (spec) rev; inherit ref; };
 
-          $ niv modify <package> -a type=tarball -a builtin=true
-      ''
-      builtins_fetchTarball { inherit (spec) url sha256; };
+  fetch_local = spec: spec.path;
 
-  fetch_builtin-url = spec:
-    builtins.trace
-      ''
-        WARNING:
-          The niv type "builtin-url" will soon be deprecated. You should
-          instead use `builtin = true`.
+  fetch_builtin-tarball = name: throw
+    ''[${name}] The niv type "builtin-tarball" is deprecated. You should instead use `builtin = true`.
+        $ niv modify ${name} -a type=tarball -a builtin=true'';
 
-          $ niv modify <package> -a type=file -a builtin=true
-      ''
-      (builtins_fetchurl { inherit (spec) url sha256; });
+  fetch_builtin-url = name: throw
+    ''[${name}] The niv type "builtin-url" will soon be deprecated. You should instead use `builtin = true`.
+        $ niv modify ${name} -a type=file -a builtin=true'';
 
   #
   # Various helpers
   #
 
+  # https://github.com/NixOS/nixpkgs/pull/83241/files#diff-c6f540a4f3bfa4b0e8b6bafd4cd54e8bR695
+  sanitizeName = name:
+    (
+      concatMapStrings (s: if builtins.isList s then "-" else s)
+        (
+          builtins.split "[^[:alnum:]+._?=-]+"
+            ((x: builtins.elemAt (builtins.match "\\.*(.*)" x) 0) name)
+        )
+    );
+
   # The set of packages used when specs are fetched using non-builtins.
-  mkPkgs = sources:
+  mkPkgs = sources: system:
     let
       sourcesNixpkgs =
-        import (builtins_fetchTarball { inherit (sources.nixpkgs) url sha256; }) {};
+        import (builtins_fetchTarball { inherit (sources.nixpkgs) url sha256; }) { inherit system; };
       hasNixpkgsPath = builtins.any (x: x.prefix == "nixpkgs") builtins.nixPath;
       hasThisAsNixpkgsPath = <nixpkgs> == ./.;
     in
@@ -71,14 +82,27 @@ let
 
     if ! builtins.hasAttr "type" spec then
       abort "ERROR: niv spec ${name} does not have a 'type' attribute"
-    else if spec.type == "file" then fetch_file pkgs spec
-    else if spec.type == "tarball" then fetch_tarball pkgs spec
-    else if spec.type == "git" then fetch_git pkgs spec
-    else if spec.type == "builtin-tarball" then fetch_builtin-tarball spec
-    else if spec.type == "builtin-url" then fetch_builtin-url spec
+    else if spec.type == "file" then fetch_file pkgs name spec
+    else if spec.type == "tarball" then fetch_tarball pkgs name spec
+    else if spec.type == "git" then fetch_git name spec
+    else if spec.type == "local" then fetch_local spec
+    else if spec.type == "builtin-tarball" then fetch_builtin-tarball name
+    else if spec.type == "builtin-url" then fetch_builtin-url name
     else
       abort "ERROR: niv spec ${name} has unknown type ${builtins.toJSON spec.type}";
 
+  # If the environment variable NIV_OVERRIDE_${name} is set, then use
+  # the path directly as opposed to the fetched source.
+  replace = name: drv:
+    let
+      saneName = stringAsChars (c: if isNull (builtins.match "[a-zA-Z0-9]" c) then "_" else c) name;
+      ersatz = builtins.getEnv "NIV_OVERRIDE_${saneName}";
+    in
+      if ersatz == "" then drv else
+        # this turns the string into an actual Nix path (for both absolute and
+        # relative paths)
+        if builtins.substring 0 1 ersatz == "/" then /. + ersatz else /. + builtins.getEnv "PWD" + "/${ersatz}";
+
   # Ports of functions for older nix versions
 
   # a Nix version of mapAttrs if the built-in doesn't exist
@@ -87,23 +111,37 @@ let
     listToAttrs (map (attr: { name = attr; value = f attr set.${attr}; }) (attrNames set))
   );
 
+  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/lists.nix#L295
+  range = first: last: if first > last then [] else builtins.genList (n: first + n) (last - first + 1);
+
+  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/strings.nix#L257
+  stringToCharacters = s: map (p: builtins.substring p 1 s) (range 0 (builtins.stringLength s - 1));
+
+  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/strings.nix#L269
+  stringAsChars = f: s: concatStrings (map f (stringToCharacters s));
+  concatMapStrings = f: list: concatStrings (map f list);
+  concatStrings = builtins.concatStringsSep "";
+
+  # https://github.com/NixOS/nixpkgs/blob/8a9f58a375c401b96da862d969f66429def1d118/lib/attrsets.nix#L331
+  optionalAttrs = cond: as: if cond then as else {};
+
   # fetchTarball version that is compatible between all the versions of Nix
-  builtins_fetchTarball = { url, sha256 }@attrs:
+  builtins_fetchTarball = { url, name ? null, sha256 }@attrs:
     let
       inherit (builtins) lessThan nixVersion fetchTarball;
     in
       if lessThan nixVersion "1.12" then
-        fetchTarball { inherit url; }
+        fetchTarball ({ inherit url; } // (optionalAttrs (!isNull name) { inherit name; }))
       else
         fetchTarball attrs;
 
   # fetchurl version that is compatible between all the versions of Nix
-  builtins_fetchurl = { url, sha256 }@attrs:
+  builtins_fetchurl = { url, name ? null, sha256 }@attrs:
     let
       inherit (builtins) lessThan nixVersion fetchurl;
     in
       if lessThan nixVersion "1.12" then
-        fetchurl { inherit url; }
+        fetchurl ({ inherit url; } // (optionalAttrs (!isNull name) { inherit name; }))
       else
         fetchurl attrs;
 
@@ -115,14 +153,15 @@ let
         then abort
           "The values in sources.json should not have an 'outPath' attribute"
         else
-          spec // { outPath = fetch config.pkgs name spec; }
+          spec // { outPath = replace name (fetch config.pkgs name spec); }
     ) config.sources;
 
   # The "config" used by the fetchers
   mkConfig =
-    { sourcesFile ? ./sources.json
-    , sources ? builtins.fromJSON (builtins.readFile sourcesFile)
-    , pkgs ? mkPkgs sources
+    { sourcesFile ? if builtins.pathExists ./sources.json then ./sources.json else null
+    , sources ? if isNull sourcesFile then {} else builtins.fromJSON (builtins.readFile sourcesFile)
+    , system ? builtins.currentSystem
+    , pkgs ? mkPkgs sources system
     }: rec {
       # The sources, i.e. the attribute set of spec name to spec
       inherit sources;
@@ -130,5 +169,6 @@ let
       # The "pkgs" (evaluated nixpkgs) to use for e.g. non-builtin fetchers
       inherit pkgs;
     };
+
 in
 mkSources (mkConfig {}) // { __functor = _: settings: mkSources (mkConfig settings); }
diff --git a/overlays/armv6l-linux.nix b/overlays/armv6l-linux.nix
index 80e4ad8639..324961f209 100644
--- a/overlays/armv6l-linux.nix
+++ b/overlays/armv6l-linux.nix
@@ -34,16 +34,16 @@ final: prev:
       in {
         packages = {
           # clock 0.7.2 needs to be patched to support cross compilation.
-          clock.patches              = pkgs.stdenv.lib.optionals pkgs.stdenv.hostPlatform.isAarch32 [ ({ version, revision }: (if version == "0.7.2" then ./patches/clock-0.7.2.patch else null)) ];
+          clock.patches              = pkgs.lib.optionals pkgs.stdenv.hostPlatform.isAarch32 [ ({ version, revision }: (if version == "0.7.2" then ./patches/clock-0.7.2.patch else null)) ];
           # nix calls this package crypto
-        #   cryptonite-openssl.patches = pkgs.stdenv.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ({ version, revision }: if version == "0.7" then ./patches/cryptonite-openssl-0.7.patch else null) ];
+        #   cryptonite-openssl.patches = pkgs.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ({ version, revision }: if version == "0.7" then ./patches/cryptonite-openssl-0.7.patch else null) ];
 
-        #   http-client.patches        = pkgs.stdenv.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ({ version, revision }: if version == "0.5.14" then ./patches/http-client-0.5.14.patch else null) ];
+        #   http-client.patches        = pkgs.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ({ version, revision }: if version == "0.5.14" then ./patches/http-client-0.5.14.patch else null) ];
 
-        #   conduit.patches            = pkgs.stdenv.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ({ version, revision }: if builtins.compareVersions version "1.3.1.1" < 0 then ./patches/conduit-1.3.0.2.patch else null) ];
-        #   streaming-commons.patches  = pkgs.stdenv.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ./patches/streaming-commons-0.2.0.0.patch ];
-        #   x509-system.patches        = pkgs.stdenv.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ./patches/x509-system-1.6.6.patch ];
-        #   file-embed-lzma.patches    = pkgs.stdenv.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ./patches/file-embed-lzma-0.patch ];
+        #   conduit.patches            = pkgs.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ({ version, revision }: if builtins.compareVersions version "1.3.1.1" < 0 then ./patches/conduit-1.3.0.2.patch else null) ];
+        #   streaming-commons.patches  = pkgs.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ./patches/streaming-commons-0.2.0.0.patch ];
+        #   x509-system.patches        = pkgs.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ./patches/x509-system-1.6.6.patch ];
+        #   file-embed-lzma.patches    = pkgs.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ./patches/file-embed-lzma-0.patch ];
 
           # Set all of these to [], as these form the
           # dependency graph of the libiserv, iserv-proxy, and iserv-remote
diff --git a/overlays/bootstrap.nix b/overlays/bootstrap.nix
index 67f2762579..c77937f87b 100644
--- a/overlays/bootstrap.nix
+++ b/overlays/bootstrap.nix
@@ -735,7 +735,7 @@ in {
               isHaskellNixBootCompiler = true;
             }
           )
-          (import ../compiler/old-ghc-nix { pkgs = final; });
+          (import sources.old-ghc-nix { pkgs = final; });
 
         packages = {
             # now that we have nix-tools and hpack, we can just
diff --git a/overlays/emscripten/binaryen.nix b/overlays/emscripten/binaryen.nix
index 3a03f633ff..14d5f14f9a 100644
--- a/overlays/emscripten/binaryen.nix
+++ b/overlays/emscripten/binaryen.nix
@@ -1,4 +1,4 @@
-{ stdenv, cmake, python3, fetchFromGitHub, emscriptenRev ? null, substituteAll }:
+{ stdenv, lib, cmake, python3, fetchFromGitHub, emscriptenRev ? null, substituteAll }:
 
 let
   defaultVersion = "93";
@@ -29,14 +29,14 @@ stdenv.mkDerivation rec {
     inherit rev;
   };
 
-  patches = stdenv.lib.optional (emscriptenRev != null) (substituteAll {
+  patches = lib.optional (emscriptenRev != null) (substituteAll {
     src = ./0001-Get-rid-of-git-dependency.patch;
     emscriptenv = "1.39.1";
   });
 
   nativeBuildInputs = [ cmake python3 ];
 
-  meta = with stdenv.lib; {
+  meta = with lib; {
     homepage = "https://github.com/WebAssembly/binaryen";
     description = "Compiler infrastructure and toolchain library for WebAssembly, in C++";
     platforms = platforms.all;
diff --git a/overlays/emscripten/default.nix b/overlays/emscripten/default.nix
index e9c0aa874d..5a69306aad 100644
--- a/overlays/emscripten/default.nix
+++ b/overlays/emscripten/default.nix
@@ -1,4 +1,4 @@
-{ emscriptenVersion, stdenv, fetchFromGitHub, emscriptenfastcomp, python, nodejs, closurecompiler
+{ emscriptenVersion, stdenv, lib, fetchFromGitHub, emscriptenfastcomp, python, nodejs, closurecompiler
 , jre, binaryen, enableWasm ? true ,  cmake, emscriptenBackend ? emscriptenfastcomp
 }:
 
@@ -45,7 +45,7 @@ stdenv.mkDerivation {
     echo "SPIDERMONKEY_ENGINE = []" >> $out/${appdir}/config
     echo "EMCC_FAST_COMPILER = 0" >> $out/${appdir}/config
   ''
-  + stdenv.lib.optionalString enableWasm ''
+  + lib.optionalString enableWasm ''
     echo "BINARYEN_ROOT = '${binaryenVersioned}'" >> $out/share/emscripten/config
   ''
   +
@@ -61,7 +61,7 @@ stdenv.mkDerivation {
     echo "--------------- /running test -----------------"
   '';
 
-  meta = with stdenv.lib; {
+  meta = with lib; {
     homepage = "https://github.com/emscripten-core/emscripten";
     description = "An LLVM-to-JavaScript Compiler";
     platforms = platforms.all;
diff --git a/overlays/emscripten/fastcomp/default.nix b/overlays/emscripten/fastcomp/default.nix
index 57496d2886..0e5286910a 100644
--- a/overlays/emscripten/fastcomp/default.nix
+++ b/overlays/emscripten/fastcomp/default.nix
@@ -1,4 +1,4 @@
-{ newScope, stdenv, binutils, wrapCCWith, symlinkJoin }:
+{ newScope, stdenv, lib, binutils, wrapCCWith, symlinkJoin }:
 let
   callPackage = newScope (self // {inherit stdenv;});
 
@@ -15,7 +15,7 @@ let
       '';
     };
     emscriptenfastcomp = symlinkJoin {
-      name = "emscriptenfastcomp-${stdenv.lib.getVersion self.emscriptenfastcomp-unwrapped}";
+      name = "emscriptenfastcomp-${lib.getVersion self.emscriptenfastcomp-unwrapped}";
       paths = [ self.emscriptenfastcomp-wrapped self.emscriptenfastcomp-unwrapped ];
       preferLocalBuild = false;
       allowSubstitutes = true;
diff --git a/overlays/emscripten/fastcomp/emscripten-fastcomp.nix b/overlays/emscripten/fastcomp/emscripten-fastcomp.nix
index 520a34afe5..c94d8ef097 100644
--- a/overlays/emscripten/fastcomp/emscripten-fastcomp.nix
+++ b/overlays/emscripten/fastcomp/emscripten-fastcomp.nix
@@ -1,4 +1,4 @@
-{ emscriptenVersion, stdenv, fetchFromGitHub, cmake, python, gtest, ... }:
+{ emscriptenVersion, stdenv, lib, fetchFromGitHub, cmake, python, gtest, ... }:
 
 let
   rev = emscriptenVersion;
@@ -34,7 +34,7 @@ stdenv.mkDerivation rec {
     #"-DLLVM_CONFIG=${llvm}/bin/llvm-config"
     "-DLLVM_BUILD_TESTS=ON"
     "-DCLANG_INCLUDE_TESTS=ON"
-  ] ++ (stdenv.lib.optional stdenv.isLinux
+  ] ++ (lib.optional stdenv.isLinux
     # necessary for clang to find crtend.o
     "-DGCC_INSTALL_PREFIX=${gcc}"
   );
@@ -45,11 +45,11 @@ stdenv.mkDerivation rec {
     inherit gcc;
   };
 
-  meta = with stdenv.lib; {
+  meta = with lib; {
     homepage = "https://github.com/emscripten-core/emscripten-fastcomp";
     description = "Emscripten LLVM";
     platforms = platforms.all;
     maintainers = with maintainers; [ qknight matthewbauer ];
-    license = stdenv.lib.licenses.ncsa;
+    license = lib.licenses.ncsa;
   };
 }
diff --git a/overlays/emscripten/upstream/default.nix b/overlays/emscripten/upstream/default.nix
index 1ac9c51ddd..cad5d15c9a 100644
--- a/overlays/emscripten/upstream/default.nix
+++ b/overlays/emscripten/upstream/default.nix
@@ -1,4 +1,4 @@
-{ newScope, stdenv, binutils, wrapCCWith, symlinkJoin }:
+{ newScope, stdenv, lib, binutils, wrapCCWith, symlinkJoin }:
 let
   callPackage = newScope (self // {inherit stdenv;});
 
@@ -15,7 +15,7 @@ let
       '';
     };
     emscriptenupstream = symlinkJoin {
-      name = "emscriptenupstream-${stdenv.lib.getVersion self.emscriptenupstream-unwrapped}";
+      name = "emscriptenupstream-${lib.getVersion self.emscriptenupstream-unwrapped}";
       paths = [ self.emscriptenupstream-wrapped self.emscriptenupstream-unwrapped ];
       preferLocalBuild = false;
       allowSubstitutes = true;
diff --git a/overlays/emscripten/upstream/emscripten-upstream.nix b/overlays/emscripten/upstream/emscripten-upstream.nix
index 1a2ed152c4..6afc0a3a81 100644
--- a/overlays/emscripten/upstream/emscripten-upstream.nix
+++ b/overlays/emscripten/upstream/emscripten-upstream.nix
@@ -1,4 +1,4 @@
-{ emscriptenVersion, stdenv, fetchFromGitHub, cmake, python, gtest, ... }:
+{ emscriptenVersion, stdenv, lib, fetchFromGitHub, cmake, python, gtest, ... }:
 
 let
   gcc = if stdenv.cc.isGNU then stdenv.cc.cc else stdenv.cc.cc.gcc;
@@ -39,7 +39,7 @@ stdenv.mkDerivation rec {
     #"-DLLVM_CONFIG=${llvm}/bin/llvm-config"
     "-DLLVM_BUILD_TESTS=ON"
     "-DCLANG_INCLUDE_TESTS=OFF"
-  ] ++ (stdenv.lib.optional stdenv.isLinux
+  ] ++ (lib.optional stdenv.isLinux
     # necessary for clang to find crtend.o
     "-DGCC_INSTALL_PREFIX=${gcc}"
   );
@@ -50,11 +50,11 @@ stdenv.mkDerivation rec {
     inherit gcc;
   };
 
-  meta = with stdenv.lib; {
+  meta = with lib; {
     homepage = "http://github.com/llvm/llvm-project";
     description = "LLVM";
     platforms = platforms.all;
     maintainers = with maintainers; [  ];
-    license = stdenv.lib.licenses.ncsa;
+    license = lib.licenses.ncsa;
   };
 }
diff --git a/overlays/haskell.nix b/overlays/haskell.nix
index 39b33a309e..8520136e25 100644
--- a/overlays/haskell.nix
+++ b/overlays/haskell.nix
@@ -266,7 +266,7 @@ final: prev: {
 
         update-index-state-hashes = import ../scripts/update-index-state-hashes.nix {
             inherit (final.haskell-nix) indexStateHashesPath;
-            inherit (final) coreutils nix writeShellScriptBin stdenv curl;
+            inherit (final) coreutils nix writeShellScriptBin stdenv lib curl;
             # Update scripts use the internal nix-tools and cabal-install (compiled with a fixed GHC version)
             nix-tools = final.haskell-nix.internal-nix-tools;
         };
diff --git a/overlays/windows.nix b/overlays/windows.nix
index de2e3176e0..7f04933726 100644
--- a/overlays/windows.nix
+++ b/overlays/windows.nix
@@ -17,11 +17,11 @@ final: prev:
   #  });
 
    mfpr = prev.mfpr.overrideAttrs (drv: {
-     configureFlags = (drv.configureFlags or []) ++ prev.stdenv.lib.optional prev.stdenv.hostPlatform.isWindows "--enable-static --disable-shared" ;
+     configureFlags = (drv.configureFlags or []) ++ prev.lib.optional prev.stdenv.hostPlatform.isWindows "--enable-static --disable-shared" ;
    });
 
    libmpc = prev.libmpc.overrideAttrs (drv: {
-     configureFlags = (drv.configureFlags or []) ++ prev.stdenv.lib.optional prev.stdenv.hostPlatform.isWindows "--enable-static --disable-shared" ;
+     configureFlags = (drv.configureFlags or []) ++ prev.lib.optional prev.stdenv.hostPlatform.isWindows "--enable-static --disable-shared" ;
    });
 
    binutils-unwrapped = prev.binutils-unwrapped.overrideAttrs (attrs: {
@@ -72,7 +72,7 @@ final: prev:
           # figuring out which libraries we need for the build (walking the
           # dependencies) and then placing them somewhere where wine+remote-iserv
           # will find them.
-          remote-iserv.postInstall = pkgs.stdenv.lib.optionalString pkgs.stdenv.hostPlatform.isWindows (
+          remote-iserv.postInstall = pkgs.lib.optionalString pkgs.stdenv.hostPlatform.isWindows (
             let extra-libs = [ pkgs.openssl.bin pkgs.libffi pkgs.gmp pkgs.libsodium ]; in ''
             for p in ${lib.concatStringsSep " "extra-libs}; do
               find "$p" -iname '*.dll' -exec cp {} $out/bin/ \;
@@ -91,20 +91,20 @@ final: prev:
           #   else null)) ];
 
           # clock 0.7.2 needs to be patched to support cross compilation.
-          clock.patches              = pkgs.stdenv.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ({ version, revision }: (if version == "0.7.2" then ./patches/clock-0.7.2.patch else null)) ];
+          clock.patches              = pkgs.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ({ version, revision }: (if version == "0.7.2" then ./patches/clock-0.7.2.patch else null)) ];
           # nix calls this package crypto
-          cryptonite-openssl.patches = pkgs.stdenv.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ({ version, revision }: if version == "0.7" then ./patches/cryptonite-openssl-0.7.patch else null) ];
+          cryptonite-openssl.patches = pkgs.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ({ version, revision }: if version == "0.7" then ./patches/cryptonite-openssl-0.7.patch else null) ];
 
           # this patch seems to be rather flaky and highly dependent on
           # the network library. I think we might need to respin that in
           # a better way that doesn't just delete some code, but makes
           # the bounds checks stricter.
-          # http-client.patches        = pkgs.stdenv.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ({ version, revision }: if version == "0.5.14" then ./patches/http-client-0.5.14.patch else null) ];
+          # http-client.patches        = pkgs.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ({ version, revision }: if version == "0.5.14" then ./patches/http-client-0.5.14.patch else null) ];
 
-          conduit.patches            = pkgs.stdenv.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ({ version, revision }: if builtins.compareVersions version "1.3.1.1" < 0 then ./patches/conduit-1.3.0.2.patch else null) ];
-          streaming-commons.patches  = pkgs.stdenv.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ./patches/streaming-commons-0.2.0.0.patch ];
-          x509-system.patches        = pkgs.stdenv.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ./patches/x509-system-1.6.6.patch ];
-          file-embed-lzma.patches    = pkgs.stdenv.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ./patches/file-embed-lzma-0.patch ];
+          conduit.patches            = pkgs.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ({ version, revision }: if builtins.compareVersions version "1.3.1.1" < 0 then ./patches/conduit-1.3.0.2.patch else null) ];
+          streaming-commons.patches  = pkgs.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ./patches/streaming-commons-0.2.0.0.patch ];
+          x509-system.patches        = pkgs.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ./patches/x509-system-1.6.6.patch ];
+          file-embed-lzma.patches    = pkgs.lib.optionals pkgs.stdenv.hostPlatform.isWindows [ ./patches/file-embed-lzma-0.patch ];
 
           # Set all of these to [], as these form the
           # dependency graph of the libiserv, iserv-proxy, and iserv-remote
diff --git a/scripts/check-closure-size.nix b/scripts/check-closure-size.nix
index 7bdae0647e..d0eeab110e 100644
--- a/scripts/check-closure-size.nix
+++ b/scripts/check-closure-size.nix
@@ -1,9 +1,9 @@
-{ stdenv, writeScript, coreutils, gawk, nix
+{ stdenv, lib, writeScript, coreutils, gawk, nix
 , nix-tools
 , limitMB ? 525
 }:
 
-with stdenv.lib;
+with lib;
 
 writeScript "check-closure-size.sh" ''
   #!${stdenv.shell}
diff --git a/scripts/check-hydra.nix b/scripts/check-hydra.nix
index 2ef9a1118d..5d43ba7de9 100644
--- a/scripts/check-hydra.nix
+++ b/scripts/check-hydra.nix
@@ -1,6 +1,6 @@
-{ stdenv, writeScript, coreutils, time, gnutar, gzip, hydra-migration, jq }:
+{ stdenv, lib, writeScript, coreutils, time, gnutar, gzip, hydra-migration, jq }:
 
-with stdenv.lib;
+with lib;
 
 writeScript "check-hydra.sh" ''
   #!${stdenv.shell}
diff --git a/scripts/check-materialization-concurrency/check.nix b/scripts/check-materialization-concurrency/check.nix
index ea0680f4c4..08edd3a5b3 100644
--- a/scripts/check-materialization-concurrency/check.nix
+++ b/scripts/check-materialization-concurrency/check.nix
@@ -1,6 +1,6 @@
-{ stdenv, writeScript }:
+{ stdenv, lib, writeScript }:
 
-with stdenv.lib;
+with lib;
 
 writeScript "check-materialization-concurrency.sh" ''
   #!${stdenv.shell}
diff --git a/scripts/check-path-support.nix b/scripts/check-path-support.nix
index 58b1c85793..c38833d850 100644
--- a/scripts/check-path-support.nix
+++ b/scripts/check-path-support.nix
@@ -1,6 +1,6 @@
-{ stdenv, writeScript, coreutils, gnutar, gzip, nix }:
+{ stdenv, lib, writeScript, coreutils, gnutar, gzip, nix }:
 
-with stdenv.lib;
+with lib;
 
 writeScript "check-path-supprot.sh" ''
   #!${stdenv.shell}
diff --git a/scripts/update-docs.nix b/scripts/update-docs.nix
index 05cb66e15a..81eeecec73 100644
--- a/scripts/update-docs.nix
+++ b/scripts/update-docs.nix
@@ -1,7 +1,7 @@
-{ stdenv, writeScript, coreutils, glibc, git, openssh, gnused, mkdocs
+{ stdenv, lib, writeScript, coreutils, glibc, git, openssh, gnused, mkdocs
 , generatedOptions }:
 
-with stdenv.lib;
+with lib;
 
 let
   repo = "git@github.com:input-output-hk/haskell.nix.git";
diff --git a/scripts/update-external.nix b/scripts/update-external.nix
index 3537154432..c47d10e8a1 100644
--- a/scripts/update-external.nix
+++ b/scripts/update-external.nix
@@ -1,10 +1,10 @@
-{ stdenv, writeScript, glibc, coreutils, git, openssh
+{ stdenv, lib, writeScript, glibc, coreutils, git, openssh
 , nix-tools, cabal-install, nix-prefetch-git
 , bash, curl, findutils, gawk }:
 
 { name, script }:
 
-with stdenv.lib;
+with lib;
 
 let
   repoHTTPS = "https://github.com/input-output-hk/${name}.nix";
diff --git a/scripts/update-hackage.nix b/scripts/update-hackage.nix
index 166ad17241..78c6d8911c 100644
--- a/scripts/update-hackage.nix
+++ b/scripts/update-hackage.nix
@@ -1,4 +1,4 @@
-{ stdenv, writeScript, coreutils, glibc, git, openssh
+{ stdenv, lib, writeScript, coreutils, glibc, git, openssh
 , nix-tools, cabal-install, nix-prefetch-git
 , gawk, bash, curl, findutils
 , update-index-state-hashes }@args:
diff --git a/scripts/update-index-state-hashes.nix b/scripts/update-index-state-hashes.nix
index e26780f607..80c6b215e3 100644
--- a/scripts/update-index-state-hashes.nix
+++ b/scripts/update-index-state-hashes.nix
@@ -1,6 +1,6 @@
-{ indexStateHashesPath, nix-tools, coreutils, nix, writeShellScriptBin, stdenv, curl }:
+{ indexStateHashesPath, nix-tools, coreutils, nix, writeShellScriptBin, stdenv, lib, curl }:
 with builtins;
-with stdenv.lib;
+with lib;
 writeShellScriptBin "update-index-state-hashes" ''
    export PATH="${makeBinPath [ coreutils nix-tools nix curl ]}"
 
diff --git a/scripts/update-pins.nix b/scripts/update-pins.nix
index 7665b351f8..382a81c49e 100644
--- a/scripts/update-pins.nix
+++ b/scripts/update-pins.nix
@@ -1,6 +1,6 @@
-{ stdenv, writeScript, coreutils, glibc, git, openssh }@args:
+{ stdenv, lib, writeScript, coreutils, glibc, git, openssh }@args:
 
-with stdenv.lib;
+with lib;
 
 let
   repo = "git@github.com:input-output-hk/haskell.nix.git";
diff --git a/scripts/update-stackage.nix b/scripts/update-stackage.nix
index d643727538..0cfa998995 100644
--- a/scripts/update-stackage.nix
+++ b/scripts/update-stackage.nix
@@ -1,4 +1,4 @@
-{ stdenv, writeScript, coreutils, glibc, git, openssh
+{ stdenv, lib, writeScript, coreutils, glibc, git, openssh
 , nix-tools, cabal-install, nix-prefetch-git
 , gawk, bash, curl, findutils }@args:
 
diff --git a/test/buildable/default.nix b/test/buildable/default.nix
index e622fe0af2..c9c664bc3d 100644
--- a/test/buildable/default.nix
+++ b/test/buildable/default.nix
@@ -1,6 +1,6 @@
-{ stdenv, cabalProject', haskellLib, recurseIntoAttrs, testSrc, compiler-nix-name }:
+{ stdenv, lib, cabalProject', haskellLib, recurseIntoAttrs, testSrc, compiler-nix-name }:
 
-with stdenv.lib;
+with lib;
 
 let
   project = cabalProject' {
diff --git a/test/builder-haddock/default.nix b/test/builder-haddock/default.nix
index 7b56f28a77..7ab535ae73 100644
--- a/test/builder-haddock/default.nix
+++ b/test/builder-haddock/default.nix
@@ -1,6 +1,6 @@
-{ mkCabalProjectPkgSet, stdenv, testSrc }:
+{ mkCabalProjectPkgSet, stdenv, lib, testSrc }:
 
-with stdenv.lib;
+with lib;
 
 let
   pkgSet = mkCabalProjectPkgSet {
diff --git a/test/cabal-22/default.nix b/test/cabal-22/default.nix
index 008b2a1db5..a98e88ad8c 100644
--- a/test/cabal-22/default.nix
+++ b/test/cabal-22/default.nix
@@ -1,6 +1,6 @@
-{ stdenv, mkCabalProjectPkgSet, cabalProject', haskellLib, util, recurseIntoAttrs, testSrc, compiler-nix-name }:
+{ stdenv, lib, mkCabalProjectPkgSet, cabalProject', haskellLib, util, recurseIntoAttrs, testSrc, compiler-nix-name }:
 
-with stdenv.lib;
+with lib;
 
 let
   project = cabalProject' {
diff --git a/test/cabal-hpack/default.nix b/test/cabal-hpack/default.nix
index a2aaa6ec36..fe981c3070 100644
--- a/test/cabal-hpack/default.nix
+++ b/test/cabal-hpack/default.nix
@@ -1,7 +1,7 @@
 # Test a package set
-{ stdenv, util, mkCabalProjectPkgSet, project', haskellLib, recurseIntoAttrs, testSrc, compiler-nix-name }:
+{ stdenv, lib, util, mkCabalProjectPkgSet, project', haskellLib, recurseIntoAttrs, testSrc, compiler-nix-name }:
 
-with stdenv.lib;
+with lib;
 
 let
   modules = [
diff --git a/test/cabal-simple-prof/default.nix b/test/cabal-simple-prof/default.nix
index 05b12c8907..03b1980773 100644
--- a/test/cabal-simple-prof/default.nix
+++ b/test/cabal-simple-prof/default.nix
@@ -1,7 +1,7 @@
 # Test a package set
-{ stdenv, util, cabalProject', haskellLib, recurseIntoAttrs, testSrc, compiler-nix-name }:
+{ stdenv, lib, util, cabalProject', haskellLib, recurseIntoAttrs, testSrc, compiler-nix-name }:
 
-with stdenv.lib;
+with lib;
 
 let
   modules = [
diff --git a/test/cabal-simple/default.nix b/test/cabal-simple/default.nix
index c00880b580..70d1d6886c 100644
--- a/test/cabal-simple/default.nix
+++ b/test/cabal-simple/default.nix
@@ -1,7 +1,7 @@
 # Test a package set
-{ stdenv, util, mkCabalProjectPkgSet, project', haskellLib, recurseIntoAttrs, testSrc, compiler-nix-name }:
+{ stdenv, lib, util, mkCabalProjectPkgSet, project', haskellLib, recurseIntoAttrs, testSrc, compiler-nix-name }:
 
-with stdenv.lib;
+with lib;
 
 let
   modules = [
diff --git a/test/cabal-source-repo-comments/default.nix b/test/cabal-source-repo-comments/default.nix
index d3f6bc48c0..776a5e1634 100644
--- a/test/cabal-source-repo-comments/default.nix
+++ b/test/cabal-source-repo-comments/default.nix
@@ -1,6 +1,6 @@
-{ stdenv, cabalProject', recurseIntoAttrs, haskellLib, testSrc, compiler-nix-name }:
+{ stdenv, lib, cabalProject', recurseIntoAttrs, haskellLib, testSrc, compiler-nix-name }:
 
-with stdenv.lib;
+with lib;
 
 let
   project = cabalProject' {
diff --git a/test/cabal-source-repo/default.nix b/test/cabal-source-repo/default.nix
index 41f0324f47..bdcec5a272 100644
--- a/test/cabal-source-repo/default.nix
+++ b/test/cabal-source-repo/default.nix
@@ -1,6 +1,6 @@
-{ stdenv, cabalProject', recurseIntoAttrs, haskellLib, testSrc, compiler-nix-name }:
+{ stdenv, lib, cabalProject', recurseIntoAttrs, haskellLib, testSrc, compiler-nix-name }:
 
-with stdenv.lib;
+with lib;
 
 let
   project = cabalProject' {
diff --git a/test/cabal-sublib/default.nix b/test/cabal-sublib/default.nix
index 89f2dbdaef..5c3458b53b 100644
--- a/test/cabal-sublib/default.nix
+++ b/test/cabal-sublib/default.nix
@@ -1,7 +1,7 @@
 # Test a package set
-{ stdenv, util, cabalProject', haskellLib, recurseIntoAttrs, testSrc, compiler-nix-name }:
+{ stdenv, lib, util, cabalProject', haskellLib, recurseIntoAttrs, testSrc, compiler-nix-name }:
 
-with stdenv.lib;
+with lib;
 
 let
   modules = [
diff --git a/test/call-cabal-project-to-nix/default.nix b/test/call-cabal-project-to-nix/default.nix
index 96c6813e43..0a436a483c 100644
--- a/test/call-cabal-project-to-nix/default.nix
+++ b/test/call-cabal-project-to-nix/default.nix
@@ -1,6 +1,6 @@
-{ stdenv, mkCabalProjectPkgSet, callCabalProjectToNix, importAndFilterProject, recurseIntoAttrs, haskellLib, testSrc, compiler-nix-name }:
+{ stdenv, lib, mkCabalProjectPkgSet, callCabalProjectToNix, importAndFilterProject, recurseIntoAttrs, haskellLib, testSrc, compiler-nix-name }:
 
-with stdenv.lib;
+with lib;
 
 let
   # This test could use cabalProject', but it does so that it
diff --git a/test/call-stack-to-nix/default.nix b/test/call-stack-to-nix/default.nix
index c6667797c3..1b87fb69a2 100644
--- a/test/call-stack-to-nix/default.nix
+++ b/test/call-stack-to-nix/default.nix
@@ -1,6 +1,6 @@
-{ stdenv, mkStackPkgSet, callStackToNix, importAndFilterProject, recurseIntoAttrs, haskellLib, testSrc }:
+{ stdenv, lib, mkStackPkgSet, callStackToNix, importAndFilterProject, recurseIntoAttrs, haskellLib, testSrc }:
 
-with stdenv.lib;
+with lib;
 
 let
   callProjectResults = callStackToNix {
diff --git a/test/compiler-nix-name/default.nix b/test/compiler-nix-name/default.nix
index adf776bd35..69b52144ff 100644
--- a/test/compiler-nix-name/default.nix
+++ b/test/compiler-nix-name/default.nix
@@ -1,6 +1,6 @@
-{ stdenv, haskell-nix, recurseIntoAttrs, testSrc }:
+{ stdenv, lib, haskell-nix, recurseIntoAttrs, testSrc }:
 
-with stdenv.lib;
+with lib;
 
 let
   project = haskell-nix.cabalProject' {
diff --git a/test/coverage-golden/default.nix b/test/coverage-golden/default.nix
index 70adfb5a85..cbdc97d043 100644
--- a/test/coverage-golden/default.nix
+++ b/test/coverage-golden/default.nix
@@ -1,6 +1,6 @@
-{ stdenv, fetchFromGitHub, recurseIntoAttrs, runCommand, testSrc, compiler-nix-name, buildPackages, sources }:
+{ stdenv, lib, fetchFromGitHub, recurseIntoAttrs, runCommand, testSrc, compiler-nix-name, buildPackages, sources }:
 
-with stdenv.lib;
+with lib;
 
 let
   # Using buildPackages.buildPackages here because buildPackages.git
diff --git a/test/coverage-no-libs/default.nix b/test/coverage-no-libs/default.nix
index 8f07fb0da3..21579685b4 100644
--- a/test/coverage-no-libs/default.nix
+++ b/test/coverage-no-libs/default.nix
@@ -1,6 +1,6 @@
-{ stdenv, cabal-install, cabalProject', stackProject', recurseIntoAttrs, runCommand, testSrc, compiler-nix-name }:
+{ stdenv, lib, cabal-install, cabalProject', stackProject', recurseIntoAttrs, runCommand, testSrc, compiler-nix-name }:
 
-with stdenv.lib;
+with lib;
 
 let
   projectArgs = {
diff --git a/test/coverage/default.nix b/test/coverage/default.nix
index 65382f73de..615f723705 100644
--- a/test/coverage/default.nix
+++ b/test/coverage/default.nix
@@ -1,6 +1,6 @@
-{ stdenv, cabal-install, cabalProject', stackProject', recurseIntoAttrs, runCommand, testSrc, compiler-nix-name }:
+{ stdenv, lib, cabal-install, cabalProject', stackProject', recurseIntoAttrs, runCommand, testSrc, compiler-nix-name }:
 
-with stdenv.lib;
+with lib;
 
 let
   projectArgs = {
diff --git a/test/exe-only/default.nix b/test/exe-only/default.nix
index 293b3d98ca..1887662b4c 100644
--- a/test/exe-only/default.nix
+++ b/test/exe-only/default.nix
@@ -1,7 +1,7 @@
 # Test a package set
-{ stdenv, util, haskell-nix, recurseIntoAttrs, haskellLib, testSrc, compiler-nix-name }:
+{ stdenv, lib, util, haskell-nix, recurseIntoAttrs, haskellLib, testSrc, compiler-nix-name }:
 
-with stdenv.lib;
+with lib;
 
 let
   project = haskell-nix.cabalProject' {
diff --git a/test/extra-hackage/default.nix b/test/extra-hackage/default.nix
index 522905dfae..40d8c40734 100644
--- a/test/extra-hackage/default.nix
+++ b/test/extra-hackage/default.nix
@@ -1,6 +1,6 @@
-{ stdenv, cabalProject', haskellLib, recurseIntoAttrs, testSrc, compiler-nix-name }:
+{ stdenv, lib, cabalProject', haskellLib, recurseIntoAttrs, testSrc, compiler-nix-name }:
 
-with stdenv.lib;
+with lib;
 
 let
 
diff --git a/test/fully-static/default.nix b/test/fully-static/default.nix
index 4d56bf2de2..15deaa4536 100644
--- a/test/fully-static/default.nix
+++ b/test/fully-static/default.nix
@@ -1,11 +1,11 @@
 { stackProject'
-, stdenv, gmp6, openssl, zlib, libffi
+, stdenv, lib, gmp6, openssl, zlib, libffi
 , buildPackages
 , recurseIntoAttrs
 , testSrc
 }:
 
-with stdenv.lib;
+with lib;
 
 let
   # Grab the compiler name from stack-to-nix output.
diff --git a/test/ghc-options/cabal.nix b/test/ghc-options/cabal.nix
index dec691d942..f39e9106fa 100644
--- a/test/ghc-options/cabal.nix
+++ b/test/ghc-options/cabal.nix
@@ -1,6 +1,6 @@
-{ stdenv, cabalProject', recurseIntoAttrs, haskellLib, testSrc, compiler-nix-name }:
+{ stdenv, lib, cabalProject', recurseIntoAttrs, haskellLib, testSrc, compiler-nix-name }:
 
-with stdenv.lib;
+with lib;
 
 let
   project = cabalProject' {
diff --git a/test/ghc-options/stack.nix b/test/ghc-options/stack.nix
index a451c2e481..65fb1ec0e4 100644
--- a/test/ghc-options/stack.nix
+++ b/test/ghc-options/stack.nix
@@ -1,6 +1,6 @@
-{ stdenv, stackProject', recurseIntoAttrs, haskellLib, testSrc }:
+{ stdenv, lib, stackProject', recurseIntoAttrs, haskellLib, testSrc }:
 
-with stdenv.lib;
+with lib;
 
 let
   project = stackProject' {
diff --git a/test/githash/default.nix b/test/githash/default.nix
index 90dcfa7421..6a674efc19 100644
--- a/test/githash/default.nix
+++ b/test/githash/default.nix
@@ -1,6 +1,6 @@
-{ stdenv, haskell-nix, recurseIntoAttrs, testSrc, compiler-nix-name, runCommand, gitMinimal, buildPackages }:
+{ stdenv, lib, haskell-nix, recurseIntoAttrs, testSrc, compiler-nix-name, runCommand, gitMinimal, buildPackages }:
 
-with stdenv.lib;
+with lib;
 
 let
   src = testSrc "githash";
diff --git a/test/index-state/default.nix b/test/index-state/default.nix
index 24962554ab..8e05755abb 100644
--- a/test/index-state/default.nix
+++ b/test/index-state/default.nix
@@ -1,7 +1,7 @@
 # Test a package set
-{ stdenv, testSrc, tool, compiler-nix-name }:
+{ stdenv, lib, testSrc, tool, compiler-nix-name }:
 
-with stdenv.lib;
+with lib;
 
 let
   # The hackage-security 0.6.0.1 was uploaded at 2020-04-06T20:54:35Z
diff --git a/test/project-flags/cabal.nix b/test/project-flags/cabal.nix
index 46bed36ea1..72f991d055 100644
--- a/test/project-flags/cabal.nix
+++ b/test/project-flags/cabal.nix
@@ -1,6 +1,6 @@
-{ stdenv, cabalProject', recurseIntoAttrs, haskellLib, testSrc, compiler-nix-name }:
+{ stdenv, lib, cabalProject', recurseIntoAttrs, haskellLib, testSrc, compiler-nix-name }:
 
-with stdenv.lib;
+with lib;
 
 let
   project = cabalProject' {
diff --git a/test/project-flags/stack.nix b/test/project-flags/stack.nix
index a6c619ff50..2e76a2a351 100644
--- a/test/project-flags/stack.nix
+++ b/test/project-flags/stack.nix
@@ -1,6 +1,6 @@
-{ stdenv, stackProject', recurseIntoAttrs, haskellLib, testSrc }:
+{ stdenv, lib, stackProject', recurseIntoAttrs, haskellLib, testSrc }:
 
-with stdenv.lib;
+with lib;
 
 let
   project = stackProject' {
diff --git a/test/setup-deps/default.nix b/test/setup-deps/default.nix
index 29e80951b0..7f3c8c313a 100644
--- a/test/setup-deps/default.nix
+++ b/test/setup-deps/default.nix
@@ -1,7 +1,7 @@
 { pkgs, compiler-nix-name }:
 
 with pkgs;
-with stdenv.lib;
+with lib;
 
 let
   project = haskell-nix.cabalProject' {
diff --git a/test/shell-for-setup-deps/default.nix b/test/shell-for-setup-deps/default.nix
index 191e7222dc..ece3e7a502 100644
--- a/test/shell-for-setup-deps/default.nix
+++ b/test/shell-for-setup-deps/default.nix
@@ -1,6 +1,6 @@
-{ stdenv, cabal-install, cabalProject', recurseIntoAttrs, runCommand, testSrc, compiler-nix-name }:
+{ stdenv, lib, cabal-install, cabalProject', recurseIntoAttrs, runCommand, testSrc, compiler-nix-name }:
 
-with stdenv.lib;
+with lib;
 
 let
   project = cabalProject' {
diff --git a/test/shell-for/default.nix b/test/shell-for/default.nix
index de4a5d139c..ff27356cc9 100644
--- a/test/shell-for/default.nix
+++ b/test/shell-for/default.nix
@@ -1,6 +1,6 @@
-{ stdenv, cabal-install, mkCabalProjectPkgSet, recurseIntoAttrs, runCommand, testSrc }:
+{ stdenv, lib, cabal-install, mkCabalProjectPkgSet, recurseIntoAttrs, runCommand, testSrc }:
 
-with stdenv.lib;
+with lib;
 
 let
   pkgSet = mkCabalProjectPkgSet {
diff --git a/test/snapshots/default.nix b/test/snapshots/default.nix
index 2247cbf802..56b897d5c8 100644
--- a/test/snapshots/default.nix
+++ b/test/snapshots/default.nix
@@ -1,6 +1,6 @@
-{ stdenv, haskellPackages, snapshots, recurseIntoAttrs, runCommand, testSrc }:
+{ stdenv, lib, haskellPackages, snapshots, recurseIntoAttrs, runCommand, testSrc }:
 
-with stdenv.lib;
+with lib;
 
 let
   env = snapshots."lts-14.13".ghcWithHoogle
diff --git a/test/stack-simple/default.nix b/test/stack-simple/default.nix
index fc2256da66..33d4d38249 100644
--- a/test/stack-simple/default.nix
+++ b/test/stack-simple/default.nix
@@ -1,6 +1,6 @@
-{ stdenv, pkgs, mkStackPkgSet, haskellLib, testSrc }:
+{ stdenv, lib, pkgs, mkStackPkgSet, haskellLib, testSrc }:
 
-with stdenv.lib;
+with lib;
 
 let
   # ./pkgs.nix and ./stack-simple.nix are generated by running
diff --git a/test/sublib-docs/default.nix b/test/sublib-docs/default.nix
index 38bbd69a09..bebb768a3f 100644
--- a/test/sublib-docs/default.nix
+++ b/test/sublib-docs/default.nix
@@ -1,7 +1,7 @@
 # Test a package set
-{ stdenv, util, cabalProject', haskellLib, recurseIntoAttrs, testSrc, compiler-nix-name }:
+{ stdenv, lib, util, cabalProject', haskellLib, recurseIntoAttrs, testSrc, compiler-nix-name }:
 
-with stdenv.lib;
+with lib;
 
 let
   project = cabalProject' {
diff --git a/test/with-packages/default.nix b/test/with-packages/default.nix
index 640a04af1a..cd15d2756d 100644
--- a/test/with-packages/default.nix
+++ b/test/with-packages/default.nix
@@ -1,6 +1,6 @@
-{ stdenv, util, mkPkgSet, recurseIntoAttrs, testSrc }:
+{ stdenv, lib, util, mkPkgSet, recurseIntoAttrs, testSrc }:
 
-with stdenv.lib;
+with lib;
 with util;
 
 let